.code-panel .code-header .file{min-width:0;overflow:hidden;text-overflow:ellipsis;white-space:nowrap}
  .code-tools{display:flex;align-items:center;gap:5px;margin-left:auto}
  .code-tool-btn{padding:5px 8px;border:1px solid #3c506e;border-radius:7px;background:#22314a;color:#dce7f7;font:700 11px/1 var(--font-ui);cursor:pointer}
  .code-tool-btn:hover{background:#2d4263;border-color:#5879a5}
  .code-panel pre{min-height:100px;flex:1 1 0}
  .learning-area{flex:0 0 auto;min-height:150px;max-height:240px;border-top:1px solid #34445e;background:#172235;display:flex;flex-direction:column}
  .learning-tabs{display:flex;gap:4px;padding:6px 8px 0;border-bottom:1px solid #2e405b;overflow-x:auto}
  .learning-tab{padding:6px 9px;border:0;border-radius:7px 7px 0 0;background:transparent;color:#91a2ba;font:700 11px/1 var(--font-ui);white-space:nowrap;cursor:pointer}
  .learning-tab.active{background:#22314a;color:#fff}
  /* 小测 tab 做题进度计数：橙色突出（已做数 / 题栈总数，作答或换题后刷新） */
  .learning-tab .quiz-count{color:#ffb02e;font-weight:800;margin-left:2px}
  .learning-panes{min-height:0;overflow:auto;flex:1}
  .learning-pane{display:none;padding:8px 10px;color:#dce7f7;font-size:12px;line-height:1.5}
  .learning-pane.active{display:block}
  .learning-pane .code-comment{max-height:none;padding:0;border:0;background:transparent}
  .teaching-goal{padding:7px 9px;margin-bottom:7px;border:1px solid #345071;border-radius:8px;background:#1d2d45;color:#cfe4ff}
  .syntax-grid{display:grid;grid-template-columns:repeat(auto-fit,minmax(190px,1fr));gap:7px}
  .syntax-card{padding:8px;border:1px solid #344b6b;border-radius:9px;background:#1a2940}
  .syntax-card.is-line-match{border-color:#ffcb66;box-shadow:0 0 0 2px rgba(255,203,102,.14)}
  .syntax-card h4{margin:0 0 4px;color:#ffd47d;font-size:12px}
  .syntax-card code{display:block;padding:4px 6px;margin:4px 0;border-radius:6px;background:#101a2b;color:#b9e3ff;font:12px/1.45 var(--font-mono);white-space:pre-wrap}
  .syntax-card p{margin:3px 0;color:#c9d6e8}
  .syntax-card .analogy{color:#b9f1d2}.syntax-card .pitfall{color:#ffc5c5}
  .line-insight{display:none;margin-bottom:7px;padding:7px 9px;border-left:3px solid #ffcb66;border-radius:6px;background:#26354c;color:#fff4d1}
  .line-insight.show{display:block}
  .thinking-pattern{display:inline-flex;padding:4px 8px;margin-bottom:7px;border-radius:999px;background:#21466a;color:#bfe1ff;font-weight:800}
  .thinking-columns{display:grid;grid-template-columns:1fr 1fr;gap:8px}.thinking-box{padding:8px;border:1px solid #344b6b;border-radius:9px;background:#1a2940}.thinking-box h4{margin:0 0 5px;color:#9fd2ff}.thinking-box ol,.thinking-box ul{padding-left:19px}.thinking-invariant{margin-top:7px;padding:7px 9px;border-left:3px solid #35bfa1;background:#183a36;color:#bff3df}
  .practice-list{display:grid;gap:7px}.practice-card{padding:8px;border:1px solid #344b6b;border-radius:9px;background:#1a2940}.practice-level{display:inline-flex;padding:2px 7px;border-radius:999px;background:#6a4d18;color:#ffe7a8;font-size:10px;font-weight:800}.practice-hint{margin-top:4px;color:#9fd2ff}
  .quiz-question{font-weight:800;color:#fff}.quiz-options{display:grid;gap:5px;margin-top:7px}.quiz-option{padding:7px 9px;text-align:left;border:1px solid #3d526e;border-radius:8px;background:#1d2d45;color:#dce7f7;cursor:pointer}.quiz-option:hover{background:#263a58}.quiz-option.correct{border-color:#35bfa1;background:#183a36}.quiz-option.wrong{border-color:#fb7185;background:#442536}.quiz-explain{display:none;margin-top:7px;color:#c7f0d8}.quiz-explain.show{display:block}
  /* 小测：自动换题倒计时 + 上一题/换一题切换（AI 在当前页面生成新小测，不切课程题） */
  .quiz-auto{display:flex;align-items:center;gap:8px;margin-top:7px;color:#ffd98a;font-size:12px}.quiz-auto[hidden]{display:none}.quiz-auto-count{flex:1;min-width:0}.quiz-auto-stay{border:1px solid #7a5c22;background:#2a2410;color:#ffd98a;border-radius:7px;padding:2px 9px;font-size:11.5px;cursor:pointer}.quiz-auto-stay:hover{background:#3a3014}
  .quiz-gen-hint{margin-top:7px;padding:6px 9px;border:1px dashed #4a6a96;border-radius:8px;background:#1a2c46;color:#9fd2ff;font-size:12px}.quiz-gen-hint[hidden]{display:none}
  /* AI 出新题时高亮突出：边框呼吸闪烁两次，题干短暂变色 */
  .quiz-card.quiz-flash{animation:quizFlash .9s ease 2;border-radius:9px}
  .quiz-card.quiz-flash .quiz-question{animation:quizFlashText .9s ease 2}
  @keyframes quizFlash{0%,100%{box-shadow:none}50%{box-shadow:0 0 0 3px rgba(255,203,102,.6),0 0 18px rgba(255,203,102,.35)}}
  @keyframes quizFlashText{0%,100%{color:#fff}50%{color:#ffcb66}}
  .quiz-nav{display:flex;gap:8px;justify-content:flex-end;margin-top:8px}.quiz-nav-btn{padding:5px 12px;border:1px solid #3d526e;border-radius:8px;background:#22314a;color:#dce7f7;cursor:pointer;font-size:12px;font-weight:600}.quiz-nav-btn:hover:not(:disabled){background:#2c4064}.quiz-nav-btn:disabled{opacity:.45;cursor:not-allowed}
  .code-line{cursor:pointer}.code-line:hover{background:rgba(159,210,255,.07)}
  .toast{position:fixed;z-index:10050;left:50%;bottom:28px;transform:translate(-50%,20px);padding:10px 16px;border-radius:999px;background:#12223d;color:#fff;box-shadow:0 12px 34px rgba(0,0,0,.25);opacity:0;pointer-events:none;transition:.22s}.toast.show{opacity:1;transform:translate(-50%,0)}
  .import-modal[hidden]{display:none}.import-modal{position:fixed;z-index:10000;inset:0;display:grid;place-items:center;padding:20px;background:rgba(10,20,36,.64);backdrop-filter:blur(8px)}
  .import-dialog{width:min(980px,96vw);max-height:92vh;display:grid;grid-template-rows:auto minmax(0,1fr) auto;overflow:hidden;border:1px solid #d7e2f0;border-radius:18px;background:#f7faff;box-shadow:0 30px 80px rgba(0,0,0,.28)}
  .import-head{display:flex;align-items:center;gap:10px;padding:14px 16px;border-bottom:1px solid #dce5f1;background:#fff}.import-head h2{font-size:18px}.import-head p{color:#6b7890;font-size:12px}.import-close{margin-left:auto;width:34px;height:34px;border:0;border-radius:9px;background:#eef3fa;color:#31425d;font-size:20px;cursor:pointer}
  .import-body{min-height:0;display:grid;grid-template-columns:minmax(0,1.2fr) minmax(280px,.8fr);gap:12px;padding:14px;overflow:auto}
  .import-editor,.import-preview{min-height:0;padding:12px;border:1px solid #dce5f1;border-radius:13px;background:#fff}.import-editor{display:flex;flex-direction:column;gap:9px}.import-editor textarea{width:100%;min-height:310px;flex:1;resize:vertical;padding:10px;border:1px solid #ccd9e8;border-radius:10px;background:#101827;color:#dce7f7;font:12px/1.5 var(--font-mono)}
  .import-row{display:flex;gap:7px}.import-row input[type=url]{min-width:0;flex:1;padding:8px 10px;border:1px solid #ccd9e8;border-radius:9px}.import-btn{padding:8px 11px;border:1px solid #c6d5e8;border-radius:9px;background:#fff;color:#27364d;font-weight:750;cursor:pointer}.import-btn.primary{border-color:#235fc7;background:#3478f6;color:#fff}.import-btn.danger{color:#b33145}.import-btn:hover{transform:translateY(-1px)}
  .drop-zone{padding:13px;border:2px dashed #b9cbe0;border-radius:11px;text-align:center;color:#61718a;background:#f7fbff;cursor:pointer}.drop-zone.drag{border-color:#3478f6;background:#eaf2ff;color:#235fc7}
  .preview-status{padding:8px 10px;border-radius:9px;background:#eef3fa;color:#4f5d73}.preview-status.ok{background:#e9f9f2;color:#157451}.preview-status.bad{background:#fff0f2;color:#aa2d43}.preview-list{display:grid;gap:6px;margin-top:9px}.preview-item{padding:7px 8px;border:1px solid #e0e7f0;border-radius:8px;background:#f8fafc;font-size:12px}.preview-item strong{color:#235fc7}.preview-warning{margin-top:7px;color:#ad6b08;font-size:11px}
  .import-foot{display:flex;align-items:center;gap:7px;padding:11px 14px;border-top:1px solid #dce5f1;background:#fff}.import-foot .spacer{flex:1}
  .feature-tip{font-size:11px;color:#6d7a90}
  @media(max-width:1000px){.code-tools .tool-label{display:none}.learning-area{max-height:215px}.import-body{grid-template-columns:1fr}.import-editor textarea{min-height:230px}}
  @media(max-width:700px){.code-tools{gap:3px}.code-tool-btn{padding:5px 6px}.thinking-columns{grid-template-columns:1fr}.import-modal{padding:6px}.import-dialog{width:99vw;max-height:98vh}.import-head p{display:none}.import-foot{flex-wrap:wrap}}